Cryptography Reference
In-Depth Information
5.3 Identity-Based Digital Signature Schemes in WSN
5.3.1 ID-Based Signature (IBS)
Definition
: The four algorithms that define the IBS scheme are
Setup
,
Key Extraction
,
Signature Generation
, and
Signature Verification
.
The
Setup
and
Key Extraction
processes are executed before the deployment of the
sensor network. Usually, the sink node or base station takes the role of a PKG and
performs the initialization process through
Setup
and key generation through the
Key
Extraction
process.
x
Î
to this algorithm, it outputs system para-
meters
PP
and a master secret
M
s
. The master secret is only known to PKG.
Key Extraction
: Given a user's identity
ID
i
and the master secret
M
s
to this algorithm, it
outputs the private-key
d
ID
i
.
ID
i
,
d
ID
i
,
and
PP
are prestored in a sensor node before deployment.
Signature Generation
: Given the message
m
M
and the private key
d
ID
i
, this algorithm
outputs the signature
.
Setup
: Given a security parameter
*
q
Signature Verification
: Given a message
m
M
, the signer's identity
ID
i
, signature
,
and system parameters
PP
, this algorithm returns valid (1) or invalid (0).
5.3.2 ID-Based Online/Offl ine Signature (IBOOS)
The IBOOS algorithm is usually used for authenticated broadcast.
Definition
: The following five algorithms define the ID-based online/offline signature
(IBOOS) scheme.
Setup
and
Key Extraction
are the same as defined in IBS.
The signature generation process is divided into two processes, namely,
Offline
Signature Generation
and
Online Signature Generation.
Offline Signature Generation
: Given the system parameters
PP
and the signing key
d
ID
i
, execution of this algorithm results in a partial offline signature
Off
. This phase
is usually executed on a resource abundant device such as a sink node or a base station
before the message to broadcast becomes available. In deployment scenarios where the
sensor network is divided into clusters, cluster heads could take the responsibility of
executing this algorithm. The resulting signature is stored on each sensor node before
it is deployed.
Online Signature Generation:
This algorithm is executed whenever a sensor node must
quickly report an event to its respective sink node or its cluster head. It is performed
on resource constraint devices such as sensor nodes. Given
m
M
,
Off
, and the time
stamp
T
s
, the algorithm generates an online signature
On
. The reuse of the partial
offline signature
Off
computed in the offline phase will considerably reduce the energy
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